X-ray tube



Feb. 14, 1939. A, KUNCKMANN 2,146,900

XLRAY TUBE Filed Nov.-14, 1936 Patented Feb. 14, 1939 i l 2 14535 UNITEDSTATES PATENT OFFICE X-RAY TUBE Arthur Klinckmann, Lombard, Ill.,assignor to Eureka X-ray Tube Corporation, Chicago, Ill. a corporationof Illinois Application November 14, 1936, Serial No. 110,916 13 Claims.(Cl. 250-145) The invention relates to an X-ray tube and the anode. Thisdisk preferably is made of a mahas as a general object to provide such atube of terial such as tungsten which is not readily new and improvedconstruction, melted by the heat generated by the bombard- A moreparticular object of the invention is ment thereof by the cathode rays.Disposed opto perfect a new and improved X-ray tube adapted posite theanode is the cathode and its support, 5 both for radiography and forfluoroscopy. comprising a metallic head I! and a cylindrical Anotherobject of the invention is to provide shield l8 sealed to the envelopeat IS, with the an X-ray tube having a divided incandescent leads forthe cathode projecting through the cathode, one portion only of which isemployed tubular extension l3. The shield is secured to for fiuoroscopy,while the entire cathode is emthe head by screws l8. The envelope, ofcourse, 10

ployed for radiography, is highly evacuated.

Yet another object is to provide an X-ray tube New and improved means isprovided herein having an incandescent cathode divided into filar ad p gs single e r u e n visua merits of unequal size but simultaneouslyoperexamination, that is fluoroscopy, as well is in able, each filamenthaving an individual focusing radiography. To that end, the cathode isdivided 15 device, so arranged that the focal spot of the into portionswith one portion arranged to be discharge from the smaller filamentfalls on and ndep ndent y energ ze for p p s 0f V sual reinforces thecenter of the focal spot of the examination and withthe entire cathodeenerdischarge from the larger filament, gized for radiography. Inaddition, individual Other objects and advantages will become apfo usingdevices for the discharge from the 20 parent from the following detaileddescription cathode are DI r each p o hereof taken in connection withthe accompanying with those devices designed to focus the dischargedrawing, in which: on the target in a manner to produce the desired Fig.1 is an elevational view of an X-ray tube qu t s of s for h flu o e pyand embodying the features of the invention. d p y Without v a g thetarg t. 25

Fig. 2 is an enlarged fragmentary view of the M e pa c l he cat ode iscomposed of an tube of Fig. 1 rotated through 90. elongated,cylindrically-wound wire filament 20 Fig. 3 is an enlarged diametricalsectional view and a smaller fi e t 2| 0f the same construct k along thli 3 3 of Fig, 2 tion. The filaments preferably are of tungsten Fig 4 isan and ti l e of t th and are mounted in the metallic head I! in identi-30 supporting head, cal manner so that the description of the mount Fig.5 is a sectional view taken along the broken ing of One Will pp y to eOther as Well. Ac- ]ine 5 5 of Fig 3, cordingly the mounting of filament20 only will Fig. 6 is a diagrammatic view of the heating be describedcurrent circuit for the cathode. One d of filament 20 ee g. is connected35 Fig 7 is a View of t target of t anode to and extends throughametallic sleeve 23 which diagrammatically illustrating the distributionof is spaced and insulated from the head I 1 by the energy of theindividual and the resultant means of a sleeve 24 of insulation, s a yporfocal spots. celain. The sleeve 24 in turn is surrounded by,

As illustrated in the drawing, for purposes of an outer metallic sleeve25 which is firmly held 40 disclosure, the invention is here embodied inan n adjusted positien y means o a set screw 26. X-ray tube having aglass envelope generally The other end of the filament is likewisesecured designated ill with a spherical intermediate porin and extendsthrough a me allic sleeve 21 tion H and oppositely disposed tubularextensions Which, however, is n d ect electrical contact i2 and i3.Projecting into the spherical portion with the metallic head IT. Thesleeve 21 is se- 45' H, through the extension I2, is a heavy rod I 4fired in Position y a set s rew 28. forming the anticathode and in thisinstance also As best Seen in the sulated end of serving as the anode ofthe X-ray tube. Th the smaller filament 2| is connected by a lead 30 rodi4 is sealed to the envelope at IS in w'ellto one end of the Secondary wd ng 3! of a known manner and th inner face of th rod is transformer 32.The insulated end of the larger 50 disposed at an angle to thelongitudinal axis of filament is Connected y a a 33 to one the tube. Inorder to increase heat conductivity, fi ed terminal-34 Of a switchgenerally designated the rod preferably is made entirelyof copper exehead With Which the remaining cept for a small disk l6 embedded in theface f ends of the filaments are in electrical contact, is

the rod which constitutes the target proper of connected by a lead 36 toone end of a small re- 55 sistance 31, the other end of whichconstitutes a second fixed terminal 38 of the switch 35. Completing theswitch 35 is a movable contact 39 connected by a lead 40 to theremaining end of the secondary winding 3| of the transformer. Theprimary 4| of the transformer is connected to a suitable source ofelectrical energy through a rheostat 42 so as to vary the quantity ofcurrent flowing in the filaments. The transformer should be wellinsulated to withstand the high voltage applied in well-known manner, bymeans not here shown, across the cathode and anode. It will be apparentfrom the foregoing that by moving the contact 39 into engagement withthe terminal 38 the smaller filament 2| only is energized, whilemovement of the contact 39 into engagement with the terminal 34 causesthe entire cathode to be energized. The larger filament 20 cannot beenergized independently of the smaller filament 2|. 4

Herein the focusing devices for thefilaments are formed directly in thehead I! and are so designed that the discharge from the larger filament20 produces a focal spot of substantial area on the disk Hi. This spotherein is substantially rectangular, see the intermediate representationof Fig. '7, with a greater concentration of energy at the periphery thanat the center of the area. The focusing device for the smaller filament2| produces a focal spot which also is rectangular but which is smallerthan the spot produced by the focusing device for the filament 2|]. Thesmaller spot has a more even distribution of energy, see the toprepresentation in Fig. '7, and moreover is located at the center of thefocal spot of the larger filament so that when the entire cathode isenergized a focal spot of large area and unusually uniform distributionresults, as shown in the lower representation in Fig. '7. Thus whenthesmaller filament 2| is employed alone the required intensity and pointorigin of X-rays desirable for visual examination are obtained, whilewith the entire cathode energized a uniform yet large focal spot isobtained so as to produce the large amount of X-rays'required forradiography without danger of melting the target.

To obtain those results, the end of the head I1 is herein formed withtwo faces 45 and 46 disposed at a large angle with one another andintersecting on a diameter of the head. The faces are disposed withtheir line of intersection in the plane of the longer diameter of theinclined end of the anode l4 (see Figs. 1 and 2) and each preferablyforms an angle of approximately 18 with a transverse plane perpendicularwith the longitudinal axis of the head. Formed respectively in the faces45 and 46 are elongated recesses 41 and 48 having their major axisextending at but a very small angle, approximately 2, with the line ofintersection of the faces. Each of the recesses 41 and 48 has an outerportion 49 and 49 respectively, the walls of which are arcuate and intransverse cross section form parts of a semi-circle. The'recess 41 hasan inner portion 50 which, in transverse section, is rectangular, whilethe recess 48 has an inner portion 5| which, in transverse section, isU- shaped; the ends of both inner portions being rounded. The portion 50is both wider and deeper than the portion 5| and the entire recess islonger in order that it may accommodate the larger filament 20. Both thefilament 2|) and the filament 2| are disposed longitudinally of therespective recesses just within the inner portion.

From the foregoing, it will be apparent that I have perfected a new andimproved X-ray tube which may be employed advantageously for use both inradiography and fluoroscopy.

I claim as my invention:

1. An X-ray device comprising a highly evacuated envelope, an anodewithin the envelope, a cathode within the envelope adapted to be heatedto incandescence, said cathode being divided into two portions ofunequal size focused to have the focal spot of the smaller portion liewithin the focal spot of the larger portion, and alternative circuitsfor energizing the smaller one only or both of said portionssimultaneously, one of said circuits including the smaller portion and aresistance and the other of said circuits including both of the portionsin series.

2. An X-ray device comprising a highly evacuated envelope, an anodewithin the envelope, a cathodewithin the envelope adapted to be heatedto incandescence, said cathode being divided into two portions ofunequal size and focused to have the focal spot of the smaller portionlie within the focal spot of the larger portion, and means forenergizing only the smaller one of said portions or all of said portionssimultaneously.

3. An X-ray device comprising a highly evacuated envelope, an anodewithin the envelope, a

cathode within the envelope adapted to be heated to incandescence, saidcathode being divided into portions focused so that the focal spot ofone portion overlies the focal spot of the other portion, andalternative circuits for energizing one only or both of said portionssimultaneously, one of said circuits including one only of the portionsand a resistance, and the other circuit including both of the portionsin series.

4. An X-ray device comprising a highly evacuated envelope, an anodewithin the envelope, a cathode within the envelope adapted to be heatedto incandescence, said cathode being divided into two portions ofunequal size, each of the portions having an individual focusing devicewith the focusing device for the larger portion producing a focal spoton the anode having an energy distribution heavier at the periphery thanat the center, and with the focusing device for the smaller portionproducing a smaller focal spot located at the center of the focal spotproduced by the larger portion, and means for energizing only thesmaller one of the portions of the said cathode or all of the portionssimultaneously.

5. An X-ray device comprising a highly evacuated envelope, an anodewithin the envelope, a cathode within the envelope adapted to be heatedto incandescence, said cathode being divided into two portions, anindividual focusing device for each portion producing a focal spot onthe anode of different size with the smaller spot located in the centerof the larger area, and means for energizing the smaller one only of theportions of said cathode or all of the portions simultaneously.

6. An X-ray device comprising a highly evacuated envelope, an anodewithin the envelope, a cathode within the envelope adapted to be heatedto incandescence, said cathode being divided into portions, a separatefocusing device for each of said portions producing a focal spot on theanode of different size when different portions are energized, and meansfor energizing the smaller one only of the portions of said cathode orall of said portions simultaneously.

7. In an X-ray device, a highly evacuated envelope, an anode in saidenvelope, a divided cathode adapted to be heated to incandescencecomprising two portions each composed of an elongatedcylindrically-wound filament, means for supporting said cathodecomprising a head having two faces disposed at a large angle to oneanother and generally directed toward said anode, an elongated recess ineach of said faces having its major axis extending generally parallelwith the line of intersection of said faces, each recess having an outerportion with arcuate side walls and an inner portion having parallelside walls, and means for supporting a portion of the cathode in each ofsaid recesses.

8. In an X-ray device, a highly evacuated envelope, an anode in saidenvelope, a cathode adapted to be heated to incandescence and dividedinto two portions, and means for supporting said cathode comprising ahead having two faces disposed at a large angle to one another andgenerally directed toward said anode, an elongated recess in each ofsaid faces constituting a focusing device having its. major axisextending generally parallel with the line of intersection of saidfaces, each recess having an outer portion with arcuate side Walls andan inner portion, the inner portion of one of said recesses intransverse cross section being generally rectangular, the inner portionof the other of said recesses in transverse cross section beinggenerally U-shaped, and means for securing a portion of the cathode ineach of said recesses.

9. In an X-ray device, a highly evacuated envelope, an anode in saidenvelope, a divided cathode adapted to be heated to incandescencecomprising two portions of unequal size, and means for supporting theportions and for focusing the discharge therefrom comprising a metallichead having on the end opposite the anode two faces disposed at a largeangle with one another, an elongated recess in each of said faces havingits larger axis extending generally parallel with the line ofintersection of said faces, one of said recesses being larger than theother to accommodate the larger portion of the cathode, each re-* cesshaving an outer portion with arcuate side walls, the larger recesshaving an inner portion which in transverse cross section issubstantially rectangular, the smaller recess having an inner portionwhich in transverse cross section is substantially U-shaped, and meansfor securing the large and the small portion of the cathode respectivelyin the large and the small recess.

10. An X-ray device comprising an elongated, evacuated envelope, ananode in said envelope having its inner end face disposed at an angle tothe longitudinal axis of the envelope, a divided cathode adapted to beheated to incandescence comprising two portions of unequal size, andmeans for supporting the portions and for focusing the dischargetherefrom comprising a metallic head having on the end opposite theanode two faces disposed at a large angle to one another with the lineof intersection of the faces lying in a plane through the major axis ofthe inclined face of the anode, an elongated recess in each of saidfaces with its major axis extending generally in the direction of theline of intersection of said faces, and means for securing a portion ofthe cathode in each of said recesses.

11. An X-ray device comprising an elongated,

' evacuated envelope, an anode in said envelope having its inner endface disposed at an angle to the longitudinal axis of the envelope, adivided cathode adapted to be heated to incandescence comprising twoportions of unequal size, and means for supporting and for focusing thedischarge from the portions of said cathode comprising a metallic headhaving on the end opposite the anode two faces disposed at a large angleto one another with the line of intersection of the faces lying in aplane through the major axis of the inclined face of the anode, anelongated recess in each of said faces with its major axis extending ata small angle with the line of intersection of said faces, and means forsecuring a portion of the cathode in each of said recesses.

12. In an X-ray device having an envelope, an anode and a cathodedivided into individual filaments disposed within the envelope, meansfor supporting the filaments and for providing focusing devices for thefilaments comprising a metallic head having its end opposite the anodedivided into two opposed faces disposed at an angle with respect to atransverse plane perpendicular to the axis of the head, a recess openingthrough each face and extending inwardly at right angles thereto, eachrecess having an outer portion with arcuate side Walls and an innerportion, one of the filaments of the cathode being mounted in each ofthe recesses just within the inner portion thereof.

13. In an X-ray device a cathode comprising an elongated,cylindrically-Wound filament, and means for supporting the filament andfor focusing the discharge therefrom comprising a metallic head havingan elongated recess opening through the end thereof in which thefilament is positioned, a metallic sleeve extending longitudinallythrough the head and secured to one end of the filament, a set screwthreaded into the head and engaging said sleeve to retain the samerigidly in fixed position, a metallic sleeve secured to the other end ofsaid filament and extending through said head, a sleeve of insulatingmaterial surrounding said metallic sleeve, a second metallic sleevesurrounding said insulation, and a set screw threaded into the head andengaging said last mentioned sleeve to retain the end of the filament infixed position.

ARTHUR, KLINCKMANN.

